1. Field of the Invention
The present invention relates generally to the field of pipe fittings, and more particularly to a fitting for coupling two sections of pipe that are connected together in a fluid tight manner that does not require welding, adhesive, the use of special tools, or other conventional techniques of permanently securing pipes.
2. Background and Description of the Prior Art
Plastic pipe has long been used for conveying fluids such as liquids and gases. Pipe fittings are utilized to connect sections of aligned pipe together. These pipe fittings must provide a fluid tight connection without any leakage over a range of operating temperatures, pressures and a variety of other surrounding conditions. For plastic pipe, however, a reliable fitting is rarely achieved owing to the stress of the fitting caused by the continuous operation of the plastic pipe or the changing of ambient conditions such as temperature and pressure. Such conditions of operation cause the fatigue of the fittings, thereby resulting in performance degradation and leakage.
Many types of pipe fittings are currently commercially available. One type is a compression fitting system. This type of fitting is rather large when compared to the pipe, and requires tools for installation. Due to the bulky size of this type of fitting, its use requires an extensive working space to provide for the installation of such fittings. When use is required in a limited space, e.g., in concrete walls, this type of fitting is very inconvenient.
Moreover, the pipe fittings of the prior art have the potential to be easily dismantled from the pipeline, which may lead to plundering of fluid within the pipeline. The pipe fitting of the present invention, however, requires some special tools to remove the pipe from the fitting thereby eliminating the possibility of any damage to the fitting or the pipe due to inadvertent dismantling while in use.
In the manufacture of the plastic pipe fitting of the prior art as discussed herein, the pipe is first inserted into the fittings and then pulled back so that the teeth of the fitting bite deeply into the wall of the pipe thereby securing the pipe to the fitting in a fluid tight manner. In general, the teeth are constructed from engineering plastics that have limited strength and that are incapable of gripping a pipe that has rather hard surface such as PVC pipe or metallic pipe. Moreover, the firmness of the grip on the pipe decreases with the rise in the temperature of the fluids conveyed through the pipe. If the teeth are totally metallic, they have to be constructed to have a very thick formation due to the portions that form corners. This causes inconvenience in the radial compression because a lot of force is required in order to compress the grip ring to confine it to the surface of the pipe. Such an operation can cause fatigue and deformation of the plastic member exerting the compressive force.
It is the primary objection of the present invention therefore to provide a plastic pipe fitting that can be used for joining two sections of pipe that are aligned in the same straight line or in the vertical direction in a fluid tight manner over a range of operating pressures and temperatures.
It is yet another objective of the present invention to provide a pipe fitting that can be easily installed without requiring any tools or specially-skilled workers.
It is yet another objective of the present invention to provide a pipe fitting that is compact in size and easy to install in narrow or restricted areas such as embedding in walls or in limited spaces, thus facilitating the installation of the pipe system.
It is yet another objective of the present invention to provide a pipe fitting that can be manufactured on an industrial scale with a production cost lower than most of the prior art, thereby allowing the fittings to be sold to the ultimate consumer at a relatively inexpensive price.